<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../js/vue.js"></script>
</head>
<body>
    <div id="root">
        姓：<input type="text" v-model='firstName'><br><br>
        名：<input type="text" v-model='lastName'><br><br>
        <!-- 调用该方法 -->
        全名：<span>{{showAllName()}}</span>
        全名：<span>{{showAllName()}}</span>
        全名：<span>{{showAllName()}}</span>
        全名：<span>{{showAllName()}}</span>
        全名：<span>{{showAllName()}}</span>
    </div>
    <script>
        Vue.config.productionTip = false; 

        let vm = new Vue({
            el: '#root',
            data: {
                firstName:'张',
                lastName:'三',
            },
            methods: {
                showAllName(){
                    // 输出了5次
                    console.log("sdfgr");
                    return this.firstName+'_'+this.lastName;
                }
            },
        });
    </script>
</body>
</html>